The Northwestern University Transgenic Core Facility is a well established, university-wide resource designed for the production of transgenic and knock-out animals for investigators of the Cancer Center, Northwestern University Medical School, Northwestern University and other affiliated institutions. Since it?s inception in 1989 as part of the Markey Program in Developmental Biology, the facility has grown steadily creating a myriad of transgenic mouse lines by pronuclear microinjection for NU investigators. Relocated in March of 1996 to Children?s Memorial Institute for Education and Research, the facility within the last few years has also been successful at creating knock-out mice for several investigators. The facility serves as a nuclear framework equipped with expensive microinjection apparatus and staffed with technically skilled individuals with expertise in microinjection, microsurgeries, embryo manipulation, cell culture and animal husbandry. Providing these services necessitates the maintenance of a large and costly animal colony. Animals are housed in state of the art caging systems to maintain a specific pathogen free level of health status allowing for their transfer readily into other animal facilities. Other services provided by the facility that take advantage of both the facility?s large stock colony and technical expertise include in vitro fertilization for rederivation or fertilization studies; embryo rederivation; breeding; and preparation of foster or timed-pregnant females. In addition, facility personnel provide consultation on all aspects of trangenesis ranging from initially seeking IACUC approval to breeding and analysis of newly created transgenic or knock-out mice. The Transgenic Core facility has a superb oversight committee which meets quarterly and is composed of faculty members from all three NU campuses. Over the last five years, the primary group of NU investigators benefiting from this shared resource have been Cancer Center members accounting for greater than 70% of the total usage. The potential to generate transgenic and knock-out animals in a timely and costly manner is critical and is an essential component of this core facility.